32 
THE FRESH-WATER LOCHS OF SCOTLAND 
the values of the uninodal and binodal periods of Loch Ness, which 
are given in the table on p. 53 below. 
During a week in July 1904, Mr E. M. Wedderburn made 
observations on Loch Earn with a roughly constructed self-recording 
limnograph of his own design. The results obtained were somewhat 
fragmentary, but they sufficed to suggest the very successful series of 
observations afterwards made on the lake in question. 
In October 1904 Mr Wedderburn installed a Sarasin limnograph 
on Loch Treig, and with the assistance of Mr Duncan Robertson, one 
of Sir John Stirling MaxwelFs gamekeepers, continuous observations 
were carried on until the well of the limnograph was destroyed by a 
storm in the following month. From these observations were deduced 
the two periods for Loch Treig given in the table on p. 53 below. 
In 1903 my attention was drawn to the subject of lake oscillations 
by Sir John Murray, and on 16th February of that year, at a meeting 
of the Royal Society of Edinburgh, I gave at his request an address 
chiefly intended to furnish a seiche-programme for the Scottish Lake 
Surveyors. In this address I gave a summary of the mathematical 
theory of stationary lake oscillations, which was afterwards published 
as a memoir " On the Hydrodynamical Theory of Seiches," Trans. 
Roy. Soc. Edin.^ vol. xli. p. 599, 1905. In a memoir "On the Calcu- 
lation of the Periods and Nodes of Lochs Earn and Treig, from the 
Bathymetrical Data of the Scottish Lake Survey," Trans. Roy. Soc. 
Edin., vol. xli. p. 823, 1905, Mr E. M. Wedderburn and myself 
applied the hydrodynamical theory to calculate the seiche periods 
of these two Scottish lakes. In what follows these papers will be 
denoted by H.T.S. and C.P.N, respectively. 
In 1905 I organised an investigation of the seiches of Loch Earn, 
to be accompanied by observations for comparison on Lochs Tay and 
Lubnaig. As the greater part of the rest of this paper is simply a 
summary of the methods and results of this investigation, I need 
merely say here that Mr James Murray, under my direction, was in 
charge of the work during the months of June and July, and that I 
was myself in immediate command during August and September, 
when I had the valuable assistance of Messrs P. White and 
W. Watson. In aid of this work, in addition to the funds of the 
Lake Survey, we had a small grant from the Government Fund 
for Scientific Research. We also had the advice and assistance of 
Mr W. N. Shaw, Director of the Meteorological Office, London, which 
were of great help on the meteorological side of our enterprise. The 
detailed report on this work (" An Investigation of the Seiches of 
Loch Earn by the Scottish Lake Survey ") has now been published in 
the Trans. Roy. Soc. Edin.^ vol. xlv. p. 361, 1906, and vol. xlvi. 
p. 455, 1908. This report will hereafter be referred to as I.S.E. 
